应用组合热电偶测量火焰温度的研究

由于火焰烟温的脉动性使得无法采用常规的3热电偶法测定真实的烟气温度。采用3热电偶法测量火焰温度时,实时测量热电偶的时间常数,对热电偶测量值进行动态补偿。测试结果表明:3热电偶测量值的相对标准偏差小于3 5%,与抽气热电偶测量值的相对偏差小于±4%。具有较好的重复性和较高的准确性,能够用于测量炉膛内真实的火焰温度。     

炉内废气循环气体浓度新模型检测方法研究

通过分析炉内废气循环过程的特点，在一定废气循环量的条件下，建立了炉内废气容积流量与废气循环次数的定量数学关系，建立了废气中氧气浓度与循环次数的定量数学关系。运用数学极限定律，得出氧的极限浓度定量数学公式，以此为基础，建立了助燃剂中氧气的浓度以及可燃混合物中氧气的浓度定量数学关系式。并以此推导出其他成分浓度的计算数学模型，为实际生产过程中不同环节的气体成分检测、分析建立了基础     

Gas Flow and Particle Transport and Deposition in a Pilot-Scale Furnace

The present work describes a computer simulation study of gas flow and particle transport and deposition in a pilot-scale furnace with cooling system. The Gambit code is used to generate the geometry and the computational grid. An unstructured mesh is generated for the pilot-scale boiler. The FLUENT code is used for evaluating the gas mean velocity, turbulence fluctuation energy, and mean pressure, as well as temperature fields and chemical species concentrations. The particle equation of motion includes the nonlinear drag, gravity, Brownian, lift, and thermophoretic forces. The gas velocity and thermal conditions in the furnace are studied. Ensembles of particle trajectories are generated and statistically analyzed. Particle deposition rates on different walls are evaluated, and the effect of particle size is studied.     

Efficient Simulation of Gas Flow in Blast Furnace

Simulation of gas flow in a multilayered non-isothermal packed bed is useful for blast furnace operators in deciding appropriate charging strategy. While using an anisotropic form of Ergun equation to simulate gas flow through such systems, a new solution methodology for non-isothermal gas with varying density flowing through a layered burden has been proposed. This involves handling non-linearity due to gas density variation with pressure and temperature by solving for the square of pressure instead of pressure directly and handling the non-linearity due to |v| term in the Ergun equation by solving linearized form of Ergun equation and updating |v| iteratively. The proposed scheme is capable of predicting the effect of layer structure on gas flow with economy in number of grid points as well as computation time.     

基于图模型的高炉气采样仿真系统

高炉气采样机实现了高炉气采样过程及样本分析的自动化。由于现场无人操作,无法监视采样机的状态,使得操作人员难以确定控制命令的效果。作者采用计算机图形学技术和系统仿真技术,建立了终端仿真根据控制系统(PLC),对采样机进行可视化模拟,从而可以控制高炉气采样过程。系统设计采用了面向对象的方法,虚拟PLC控制系统采用图形交互的设计思想。     

涟钢50MW联合循环机组热工综合测试研究

通过大修前后涟钢50MW高炉煤气燃气-蒸汽联合循环机组的热工综合测试,得到了机组的热力性能,分析了燃料热值、燃料旁通流量和大气温度等因素对联合循环影响该机组热力性能的影响,提出了增加出力、降低热耗的改进措施和建议。     

Evolution of Charging Programs for Achieving Required Gas Temperature Profile in a Blast Furnace

This article presents an approach by which charging programs in the blast furnace can be evolved. The core of the method is a mathematical model, which on the basis of a given charging program estimates the two-dimensional distribution of burden layers in the shaft. A gas flow model uses this information to estimate the gas distribution, applying a simplified treatment of the conditions in the upper shaft. The aim is to find the charging program that gives a state of the furnace shaft matching a target for the radial temperature profile at the level of an in-burden probe. This is accomplished by applying a genetic algorithm (GA) that makes an efficient search among the huge number of potential charging programs, executing the burden and gas flow models in the function evaluations. The method is illustrated by six cases, where targets for the gas temperature distribution are given and the GA evolves the charging sequence and the chute settings for the dumps. It is demonstrated that the algorithm efficiently can evolve charging programs which yield temperatures in agreement with the targets, which holds promise for a practical application of the method in the steel plant.     

Gas particle industrial flow simulation using RANSTAD

A turbulent gas particle finite-volume flow simulation of a representative coal classifier is presented. Typical values of the loading ratio permit a one-way coupling analysis. As a case study, the computational fluid dynamics code,ranstad, and the modelling aspects are discussed in some detail. The simulation indicates that small (≈ 30 μm) coal particles pass through the classifier to the furnace but that large (≈ 300 μm) particles are captured and remilled. The computational simulation indicates that the classifier performance can be improved by internal geometric modification. The commitment of the Electricity Commission of New South Wales (Pacific Power) to the exploitation of Computational Engineering for the improvement of all aspects of electricity generation is acknowledged.     

浮法玻璃熔窑烟气治理和利用

本文阐述了浮法玻璃熔窑的运行特点和烟气特性,对国内应用的烟气脱硫、脱硝技术进行了分析比较,结合浮法玻璃熔窑工艺特点,提出了几种适合浮法玻璃生产线的脱硫脱硝除尘余热发电一体化工艺方案和相关建议。     

Regimes of Dissociation of Gas Hydrates Coexisting with a Gas in Natural Strata

A mathematical model of decomposition of gas hydrates that coexist with a gas in natural strata is proposed; the model takes into account the mobility of the liquid phase. Conditions at the unknown boundary of dissociation are derived. In the self-similar approximation, the solution is represented in the form of probability integrals. The obtained system of transcendental equations at the moving boundary has been investigated numerically in a wide range of parameters. It is shown that different regimes of dissociation in collectors with a positive initial temperature exist; these regimes correspond to the decomposition of a hydrate into gas and water and gas and ice and have both a sharp phase-transition front and are accompanied by the formation of an extended region of dissociation. On the plane of the main parameters of the process, the critical diagram is constructed and the existence domains of the solution of each form are singled out.     

金属氧化物半导体气敏传感器稳定性研究进展

金属氧化物半导体(MOS)气敏传感器的稳定性是气敏器件实用化进程中最具有挑战性的因素。影响器件稳定性的主要因素包括颗粒尺寸、颈部宽度、微裂纹、电极、湿度和温度的变化。颗粒的长大和颗粒间颈部尺寸的变化降低了耗尽层对总电阻变化的贡献;微裂纹的加剧使器件的电阻发生漂移,并且为水蒸气、氧气和待测气体扩散到敏感膜内部提供便捷的通道;电极的退化影响电极与气敏材料之间的接触电阻Rc;温度和湿度的改变使气体的吸附、脱附、反应活性和电子迁移率等都发生变化,因而器件的稳定性得不到保证。在机理分析的基础上,分别介绍了提高器件稳定性的方法。     

FM全新卡车顶篷把手气辅成型技术

研究了气辅成型过程中气体穿透聚合物熔体的扩散特征和气.熔界面形态.以FM全新卡车顶篷把手为典型件进行气辅成型实验研究,研究了气体保压压力、熔体温度、气体保压时间、气体注射延迟时间四个重要工艺参数对气熔界面的影响规律.结果表明,在气体注射点近区,气体对聚合物熔体冲击程度较大.呈现出复杂流动形态及扩散特征;低的保压压力和熔体温度,较短的保压时间和较长的气体注射延迟时间可获得较好的气熔界面.     

40CrNiMoA钢曲轴井式电阻炉中气体渗氮工艺的改进

采用井式电炉气体渗氮工艺对40CrNiMoA钢制曲轴进行渗氮处理时,原渗氮工艺存在氨气消耗量大,设备老化严重和产品质量不合格等问题,因此进行了渗氮工艺的改进。结果表明：通过采用降低渗氮温度、对工件进行充分预氧化、对马弗罐定期进行退氮和合理控制氨气流量等新工艺后,产品质量和设备利用率均得到提高,氨气消耗量降低,因而渗氮成本大幅下降。     

SIMULATION OF GAS FLOW IN BLAST FURNACE FOR DIFFERENT BURDEN DISTRIBUTION AND COHESIVE ZONE SHAPE

Blast furnace is a very complex physico-chemical process with countercurrent flow of gas and solid. Computation of gas flow through different regions of blast furnace can be considered as the first major step towards numerical simulation of the process. Gas velocity profile in blast furnace depends on the burden distribution and shape of the cohesive zone, which affect the overall thermal efficiency and utilization of reduction potential of the gas (CO/CO₂ratio). Nonuniform or high gas flow near the wall causes overheating of the wall, which leads to high rate of refractory erosion and heat loss. High gas flow through the central region, on the other hand, causes higher CO/CO₂ratio at the center, leading to reduction in chemical and thermal efficiency of the gas. Therefore, achieving an optimum gas flow by controlling the burden distribution and shape of the cohesive zone is very important for minimizing refractory loss, thermal and chemical efficiency of the process. Gas velocity through various zones of blast furnace is computed by solving vectorial Ergun's equation for flow through porous medium considering axi-symmetric condition. To incorporate the shape of blast furnace efficiently, one-dimensional stretching in radial direction or nonorthogonal body-fitted coordinate system is used by the standard (x,y)to (ξ,η)transformation method. This model can be used for optimizing burden distribution and developing gas velocity control systems for blast furnace.     

The influence of flue gas recirculation on oxy-oil combustion in an existing furnace

Oxy-fuel combustion has received increasing attention as one of the major solutions for CO₂ capture. This study aimed to obtain a better understanding on the oxy-oil firing process and to gain experience handling flue gas recirculation. A 300 kW_th multi-fuel combustion test furnace at National Cheng-Kung University in Tainan, Taiwan was chosen as the experimental facility. This experimental study had successfully converted a conventional air-fired furnace to operate on oxy-fuel firing with various operating conditions. Oxygen-enriched combustion and oxy-fuel combustion tests were conducted. The effects of oxygen enrichment, flue gas recirculation, fuel type, and thermal loading on the operational characteristics of the furnace such as temperature distribution, pressure variation, and emission characteristics were examined and discussed. Several concerns about a conventional air-fired furnace adapted for oxy-fuel combustion were scrutinized, including optimization of flue gas recirculation for better combustion efficiency, higher SO₂ concentration in the flue gas under oxy-fuel operation, and air leakage coming from negative pressure operation. These findings provided valuable data to improve the performance of oxy-fuel combustion and to allow better conceptual designs in future development.     

精准纳米气体治疗研究进展

精准纳米气体治疗具有低毒高效等特性, 作为一种新兴的疾病治疗手段受到越来越多的关注。研究表明, 纳米气体治疗不仅能在特定疾病部位选择性杀死癌细胞, 还能保护正常细胞。本文总结了国际最新研究成果, 对精准纳米气体治疗的最新研究进展进行了总结归纳和展望。首先, 阐述了纳米气体治疗的治疗作用和特点; 然后, 总结了实现精准纳米气体治疗的主要途径, 包括靶向气体传输、可控气体释放、医学成像引导和监控气体治疗、基于治疗性气体的多模式联合治疗等; 最后, 对纳米气体治疗存在的问题和发展前景做出了总结和展望。     

气相色谱法测定液化石油气中异戊烷含量的不确定度评定分析

通过应用现代数理统计方法对液化石油气组分中异戊烷含量测量不确定度来源进行分析,获得了各单项的不确定度,并计算出合成不确定度,对其进行了量化评定。不确定度主要来源于峰面积引入的不确定度和标准物质引入的不确定度。     

结合燃气-蒸汽联合循环的液化天然气冷能发电利用

提出了结合燃气-蒸汽联合循环的利用液化天然气（liquefied natural gas,LNG）冷能的朗肯循环发电系统,实现LNG冷能梯级利用。朗肯循环蒸发器和燃气-蒸汽联合循环凝汽器换热量匹配一致,循环水系统实现闭式且不受环境温度影响。对系统进行模拟并分析了影响系统的主要参数,结果显示：随着朗肯循环冷凝温度的降低,朗肯循环净输出功率和净效率均有提升;随着循环水温度的提高,朗肯循环的净输出功率和净效率都将提高,而蒸汽轮机输出功率减少,但二者总的输出功率降低幅度不大。     

PIROGAS - a new process allowing diversification of energy sources for blast furnaces

The PIROGAS process consists in replacing, in part or in total, the hot blast blown through the blast furnace tuyeres by reducing gas heated to a temperature of about 2000°C. The heating or the overheating and, eventually, the production of the reducing gas, can be achieved directly in the plasma heater. Up to 80% of the coke required for a conventional blast furnace operation can be replaced by substitute fuels. The PIROGAS process makes it possible to optimize the ratio between fossil fuels and electric power consumption to achieve an economic optimum. Trials carried out on an experimental blast furnace have shown that an operation with co'~e consumption as low as 105 kg of coke/ton of hot metal can be easily attained. Furthermore, it appeared during these trials that the quality of the hot metal can be instantaneously modified by appropriate action on reducing gas temperature and composition. Thus, the control of the process becomes easier and more rapid. Trials carried out on a full size commercial blast furnace have confirmed that the plasma heater in no way disturbs the operation of the blast furnace and, reciprocally, the unavoidable fluctuations in blast furnace operation do not perturb the functioning of the plasma heater. Plasma heaters have a high thermal efficiency (80%) and their electrical behaviour is excellent (power factor 0.92; no harmonics).     

出租车燃气化改装经济系统仿真研究

燃气汽车规模化发展问题是我国乃至世界环境保护的一个重要问题。选取了燃气汽车规模化发展互动过程中的一个有代表性的部分——出租车燃气化改装为研究重点，运用系统动力学中的相关分析工具，建立了规模化发展过程中，燃油出租车燃气化改装的系统动力学模型。重点研究了模型的实现问题，对相关的算例进行了仿真。